Human physiology, and in turn psychology, functions and is largely determined by light exposure. The majority of organisms on the planet, including humans, have developed finely tuned circadian clocks synced to Earth’s light-dark cycle. In addition, we synthesize vitamin D and other important compounds when our skin is exposed to sunlight. Altering our experience of this natural cycle by adding artificial light at night and spending the day indoors can have serious health consequences. This course explores healthy habits around light and how to design and/or modify spaces with lighting that optimizes human health while minimizing the environmental burden and carbon footprint.